Television cabinet switch



Oct. 14, 1941.

TELEVISION CABINET SWITCH Filed Dec. 24, 1938 r0 POWER SUPPLYE 2 g bows/z 5 PACK L 9L. L Lows 01 x36;

D-C- 1/ l/ INVENTORS HANS OTTO ROOSENSTEIN ERNs'r' REIMANN CS/W ATTORNEY H. o. ROOSENSTEIN ETAL Patented Oct. 14, 1941 TELEVISION CABINET SWITCH Hans Otto Roosenstein and Ernst Reimann,

Berlin, Germany,

assignors to Telefunken Gesellschaft fur Drahtlosc Telegraphic m. b. H., Berlin, Germany, a corporation of Germany Application December 24, 1938, Serial No. 247,606

Germany December 23, 1937 1 Claim.

This invention relates to a new and novel arrangement for a television cabinet switch.

An object of the invention is to provide a supply line switch in television cabinet receivers which is to be actuated by a cover.

In television receivers in which the picture is viewed in a mirror mounted in the cover of the cabinet, it is liable to happen that after completion of a program, the lid is lowered, while the disconnection of the supply mains is inadvertently overlooked, very much to the detriment of the tubes, particularly of the costly cathoderay tube.

In television technique, it is usually customary to transmit the video signal from which the electro-optical reproductions result, on a carrier frequency which is spaced a fixed amount from a carrier frequency upon which the accompanying sound or audio modulation takes place. In operating receivers of this nature one generally tunes to the sound or audio modulated carrier, whereupon the video modulations cause the desired form of electro-optical reproductions on the screen. Sometimes it is desirable to provide a system wherein it is not necessary to watch the video reproduction or to have the cabinet lid with its reflector opened to a viewing position. Under such circumstances, the switch element may be so arranged as to disconnect th power supply only to those elements of the complete receiver to which relatively high voltages are supplied, or in other words, to disconnect the power supply only from the video channel, but to maintain in a connected state the power supply which is to energize the complete audio channel, any radio frequency amplifiers, the oscillators, and the converters, as well as the automatic frequency control and automatic volume control units. This would leave in an inoperative state upon the closure of the cabinet cover, only the video modulated and intermediate frequency amplifiers, the video detector and any necessary amplifiers, as well as the deflection voltage sources.

The invention discloses ways and ,means capable of insuring switching ofi of the entire receiver circuit or a portion thereof automatically together with the closing of the cabinet cover. The cover causes release of a contact whereby the desired apparatus is disconnected with the supply line either in one or in both poles.

The drawing illustrates the receiver casing or cabinet shown in section. When closing the lid 5 of the cabinet, a pin I is depressed so that spring 2 which is secured to the cabinet by a support 3 is bent away from the fixed contact 4, with the result that the entire receiver circuit or a portion thereof is interrupted. When cover 5 releases the pin I, which is moved upward by spring force, the spring 2 then makes a contact with 4. The circuit arrangement of the drawing shows the supply line 6 broken by means of connections made to points 3 and 4, which points are connected in series with the primary of a transformer 1, the secondary of which connects to a power pack 8 having low voltage output terminals 9 and high voltage direct current output terminals Hi. The cathode ray tube ll connects to high voltage terminals ID, the connections to deflecting plates not being shown completed as they may be either electrostatic or electromagnetic control or a combination of both, as the latter connections do not affect the operation of this invention. The circuit arrangement described above shows but a simple single-pole switch breaking the primary of the transformer. The pin I may break other circuit connections by being provided with a plurality of contacts and switch arms, such as for example, the high and low voltage terminals 9 and [0, so that the cathode ray tube II is entirely disconnected and the sound reproducing means remaining connected.

What is claimed is:

A television receiver comprising an electrooptical image reproducing means, a housing cabinet for said image reproducting means, a pivoted cover closing said cabinet, a reflector supported in the inside surface of said cover for observing in one position a reflected image reproduced by the reproducing means and in a second position for protecting and for housing completely the image reproducing means, a source of energizing voltage for said image reproducing means, a power supply for sound reproducing means, and switching means operatively connected with the cover for disconnecting the source of energizing voltage when said cover is in the above named second position without disconnecting the power supply tor the sound reproducing means.

ERNST REIMANN. HANS OTI'O ROOSENSTEIN. 

